Alphabetically smallest word P84412

Given a string $s$ made up of only lowercase letters, and a natural number $k$, remove any substring of length $k$ from $s$ so that the result is the lexicographically smallest possible word.

Input

Input consists of several cases, each with $s$ and $k$. Assume $1 \le k < \vert s \vert \le 10^4$.

Output

For every case, print the alphabetically smallest word that can be obtained after removing $k$ consecutive letters from $s$.